In our increasingly waste-conscious world, tremendous strides have been made with respect to recycling synthetic materials. Significant progress has been made, in particular, in the area of polyester products, such as polyethylene terephthalate (PET) products. Total global tonnage of such products is in the tens of millions, primarily in the form of textiles and packaging (e.g., PET bottles). Recycling and reuse of the polymer material in PET bottles has become particularly widespread, and such recycling processes typically include mechanical processing techniques that produce polymer chips that can be used as a feedstock in a variety of polyester product manufacturing processes including those used to make textiles.
However, use of recycling techniques for synthetic fiber products such as textiles has not reached the same level of widespread acceptance. One problem associated with synthetic fiber recycling is the fact that virtually all synthetic fibers are colored as part of the manufacturing process. Although many thermoplastic fibers can be melted and either extruded or injection molded into new products, the presence of colorant in the polymer material reduces the commercial attractiveness of many synthetic textile materials otherwise available for recycle and reuse.
Certain recycling processes have been proposed for polyester materials that includes dye removal steps. See, for example, U.S. Pat. No. 7,192,988 to Smith et al. and U.S. Pat. No. 7,959,807 to Mukai et al. However, both of the above-noted patents also suggest depolymerization and repolymerization steps, which greatly increase the cost and complexity of those processes.